Justification of the use of cell culture in the epidemiological surveillance system for tick-borne infections
Year: 2026
Type: article
Abstract: BACKGROUND: The development of new approaches to studying changes in Rickettsia populations is necessary for an objective assessment of the epidemic activity in foci of rickettsioses. The comprehensive application of classical and modern molecular biological methods for the detection and study of rickettsiae has led to the development of an algorithm for the microbiological monitoring of natural foci of tick-borne rickettsioses. This algorithm allows for the identification of both highly virulent strains and genetic variants with reduced virulence within the structure of Rickettsia populations circulating in a specific territory. AIM: To compare various methods for the detection and identification of tick-borne spotted fever group rickettsiae, and to justify the strategy for applying these methods to assess the structure of Rickettsia populations and natural foci of tick-borne rickettsioses. METHODS: The following generally accepted research methods were used: zoological and parasitological; epidemiological (retrospective analysis using descriptive and analytical studies); rickettsiological (cultivation of rickettsiae in cell cultures and in bioassays using male guinea pigs); serological (indirect immunofluorescence assay, complement fixation test, enzyme-linked immunosorbent assay); molecular biological (PCR, Sanger sequencing); and statistical. The study was conducted in accordance with the methodological guidelines MU 3.1/4.2.4140-25 “Epidemiological surveillance, laboratory diagnosis, and prevention of tick-borne rickettsioses.” The study materials were: adult ixodid ticks (326 specimens); Rickettsia strains (15 strains of the following species: Rickettsia sibirica, R. slovaca, R. heilongjiangensis, R. conorii, R. raoultii, as well as strains of the ancestral group Candidatus R. tarasevichiae); cell cultures (Vero and HEp-2); and blood sera from patients with tick-borne infections (1116 paired and 314 single blood sera). RESULTS: Cell culture was used as an additional method for the cultivation of strains of known pathogenic Rickettsia species (R. sibirica, R. heilongjiangensis, R. slovaca) previously isolated in guinea pigs and chicken embryos. This method was also used to study rickettsiae of new genotypes that are uncultivable or poorly cultivable in classical models (R. raoultii, Candidatus R. tarasevichiae). Using cell cultures, whole cell soluble and corpuscular antigens were obtained, which were used to develop Slide Antigen test systems based on enzyme linked immunosorbent assay. Furthermore, whole cell soluble antigens were used to perform serological tests with patients’ sera. CONCLUSION: Cell culture represents an effective model for the isolation, study, and accumulation of rickettsiae, as well as for the creation of diagnostic preparations. It opens up opportunities to study the geographical distribution of previously known and new Rickettsia species and to assess their role in human pathology.
DOI: 10.17816/eid702603
Language: English
Subfield: Parasitology
Field: Immunology and Microbiology
Domain: Life Sciences
Open Access status: diamond
OpenAlex ID: W7204155931